From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Subject: Re: Re: [PATCH] Add ALUA hardware handler Date: Thu, 11 Oct 2007 12:47:29 -0500 Message-ID: <470E61B1.4080007@cs.wisc.edu> References: <470CCBB0.2020904@suse.de> <470D1DAE.1000900@cs.wisc.edu> <470DDF6F.5090909@suse.de> <470E5B37.1060902@cs.wisc.edu> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <470E5B37.1060902@cs.wisc.edu> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development Cc: Alasdair G Kergon , SCSI Mailing List , christophe varoqui List-Id: linux-scsi@vger.kernel.org Just some thoughts Mike Christie wrote: >> This is actually by design. Problem here is the port group as returned by >> REPORT TARGET PORT GROUPS does not have any association to the controller >> which handles these ports. So I agree the hw handler just knows that it has paths unless you do something like chandra and send commands to figure out the contoller mappings. But are you saying that in userspace during dm mpath device setup time, there is no way to figure out the mappings? We talked about making the controller mappings and handling the problem where you cannot flood the box and the problem of having to send multiple commands more generic. We did not do that for rdac at the time because we thought scsi hw handlers were going to be done sooner, and did not want to redo the effort, but if it helps it could be done.